Research On Leaf Wettability And Water Retention Capability Of Plants In Loess Hilly-gully Region

Loess hilly-gully region is one of the most vulnerable areas on the Loess Plateau of China, and locates in the transition zone between forest and grassland. Arid climate condition, sparse rainfall and shortage of water resources make soil moisture to be the main restriction factor of vegetation restoration and ecological construction. Rainfall is the main water source of vegetation growth and distribution in the region. When rain event occurs, plant canopy would redistribute the rainfall. The canopy interception will make influence on the total rain water which reaches the ground soil, and then impact on the water transmission between soil, vegetation and atmosphere interface. Plant leaf wettability is one important microcosmic indice for clarifying plant rainfall interception and quantifing the canopy interception process. In this work, a total of 41 plants containing Bothrichloa ischaemum and Lespedeza davurica belonging to 19 different families were selected to investigate the leaf morphological index(e.g leaf length, leaf width, leaf thickness and specific leaf area), leaf wettability and leaf maximum water storage capacity of plants in June(the dry season) and August(the rainy season) at different habitats(i.e. sunny and cloudy slopes, mountain and lower land).The main results were as follows:1. The plant leaf wettability changed with habitats. The leaf wettability of plants in lowr land had significant higher leaf wettability than that in mountains. The leaf wettability of plants in cloudy slopes is significant higher than that in sunny slopes. The leaf wettability of plants in rainy seasons is significant higher than that in dry seasons.2. The leaf wettability of tree species is significant higher than those of shrubs and herbs, but no obvious difference is found between shrubs and herbs.3. There is a positive correlation between the leaf wettability and leaf age, and older age leaf had higher mean leaf wettability.4. By immersion method, results show that there is a significant positive correlation between the maximum water storage capacity and the leaf wettability.5. Within the same family, the specific leaf area of plant in cloudy slopes and lower land habitats was significant higher than those in sunny slopes and mountain slopes, respectively.